ensure a good clock() value for usage and tests

We use clock() as a very cheap way of getting a "random" value, but the
manpage warns that this could return -1, so we should be dealing with
this. Additionally, e.g. on hurd-i386 the value increases only slowly –
to slow for our fast running tests for randomness hence producing the
same range in both samples, so we introduce a simple busy-wait loop (as
clock is counting processor time used by the program) in the test which
delays the second sample just enough making our randomness a bit more
predictable.

1 files changed, 1 insertions, 1 deletions

diff --git a/apt-pkg/contrib/srvrec.cc b/apt-pkg/contrib/srvrec.cc
index be159bad9..327e59937 100644
--- a/apt-pkg/contrib/srvrec.cc
+++ b/apt-pkg/contrib/srvrec.cc
@@ -185,7 +185,7 @@ SrvRec PopFromSrvRecs(std::vector<SrvRec> &Recs)
 	 [&I](SrvRec const &J) { return I->priority != J.priority; });
 
    // clock seems random enough.
-   I += clock() % std::distance(I, J);
+   I += std::max(static_cast<clock_t>(0), clock()) % std::distance(I, J);
    SrvRec const selected = std::move(*I);
    Recs.erase(I);